KR20070093071A - Low water-absorptive polyimide resin and method for producing same - Google Patents

Abstract

Disclosed is a polyimide resin obtained by reacting a compound selected from 1,2,4,5-cyclohexanetetracarboxylic acid, acid dianhydrides thereof and reactive derivatives of them with a compound selected from diamines containing at least one phenylene group and an isopropylidene group and diisocyanates. Such a polyimide resin is colorless and has high heat resistance, high transparency and low water absorption.

Description

Low-absorbency polyimide resin and its manufacturing method {LOW WATER-ABSORPTIVE POLYIMIDE RESIN AND METHOD FOR PRODUCING SAME}

The present invention provides a colorless transparent low-absorbency polyimide resin, a method for producing the same, a method for producing a film made of the polyimide resin, and a sealing material containing the polyimide resin.

Generally, a polyimide resin is a heat resistant resin obtained by carrying out dehydration ring-closure reaction of the polyamic acid obtained by condensation reaction of aromatic tetracarboxylic anhydride and aromatic diamine. Due to the rigidity, resonance stabilization and strong chemical bonding of the molecular chain, it has excellent thermal decomposition resistance and resistance to chemical changes such as oxidation and hydrolysis, and has excellent mechanical properties, electrical properties and flexibility, so that the electric, electronic, automotive and aerospace industries It is widely used as a film, a coating agent, a molded part, and an insulating material in such fields.

However, in general, the aromatic polyimide resin film is colored yellow or brown by absorption of visible light resulting from the formation of intramolecular or intermolecular electron transfer complexes, so that substrate materials such as flat panel displays and mobile telephone devices, It was not suitable for optical applications, such as an optical fiber, an optical waveguide, and optical adhesives. In such optical applications, there is an urgent need for technology development of transparent high heat resistant resins having flexibility, heat colorability and mechanical strength.

Polymethyl methacrylate, which has been used as an optical plastic, has low birefringence and colorless transparency, but cannot be used for the optical application because it lacks heat resistance. Moreover, although polycarbonate has a comparatively high glass transition temperature, it cannot satisfy | adopt because of the fault that it does not satisfy | fill the heat-resistant coloring property required for the said optical use, and its birefringence is also large.

Colorless transparency, easy formability, and heat resistance are required for the sealing material of photoelectric conversion devices such as light emitting diodes (LEDs) and optical sensors. In particular, epoxy resins excellent in these performances have been widely used as LED sealing materials (see Patent Document 1). In recent years, development of a light emitting material advances, and LED has become high brightness, and the thing with short emission wavelengths, such as blue and an ultraviolet-light, has spread. In connection with this, the encapsulation material is exposed to light of higher temperature or higher energy. Existing epoxy resins lack heat resistance and light resistance, and it was difficult to maintain colorless transparency for a long time such as coloring (yellowing). Moreover, although lead-free soldering of solder is progressing from a viewpoint of environmental protection, mounting temperature of LED also tends to increase with this. Conventional epoxy resins have a problem that lead-freeization is difficult because of insufficient heat resistance.

On the other hand, the examination which uses silicone resin as a sealing material excellent in heat resistance and light resistance is performed. However, the silicone resin has a drawback that the adhesiveness is insufficient and soft, and there is a problem in the reliability of the device. In addition, when silicone resin is used for the sealing material, in the high temperature environment at the time of mounting a device, electrical contact defect may arise due to the volatile component which arises from resin. Moreover, according to Snell's law, in order to improve the light extraction efficiency of LED, it is preferable that the refractive index of the sealing material in a light emission wavelength range is high. On the other hand, since the refractive index of the existing epoxy resin or silicone resin is generally less than 1.55, the sealing material which has higher refractive index is calculated | required.

Moreover, since the epoxy resin and silicone resin which are conventionally used for sealing LED devices are thermosetting resins, there existed a problem that hardening at the time of sealing takes time, and manufacturing time becomes long. On the other hand, the method of sealing an LED device by injection molding a thermoplastic resin is proposed (refer patent document 2). However, this method has a problem that the sealing resin becomes incomplete because the sealing resin softens and deforms in a high temperature environment at the time of LED mounting.

As a material which solves such a problem, the colorless transparent polyimide resin is proposed. As a polyimide resin which has high heat resistance and transparency, the fluorinated polyimide resin containing the repeating structural unit which has a perfluoroalkyl group is reported (refer patent document 3 and patent document 4). Since fluorinated polyimide resin lacks solvent solubility, it casts and forms a polyamic acid which is poor in storage stability, and heat-imide-forms it at the high temperature of 350 degreeC, and is shape | molded in the film. Since it contains fluorine, it is easy to color yellow by heat treatment at the time of film formation or imidization, and surface smoothness is unstable, and there exists a defect that it is difficult to control film thickness.

The technique of obtaining the polyimide resin which can be heat-melted using a 1,2,4,5-cyclohexane tetracarboxylic dianhydride is disclosed (refer patent document 5). In Example 1, 1,2,4,5-cyclohexanetetracarboxylic dianhydride is reacted with diaminodiphenylmethane to obtain polyamic acid, which is heated to imidize, and the resulting polyimide is heated under pressure molding. , A transparent yellow polyimide resin film having a glass transition temperature of 304 ° C. is produced. In addition, it has been reported that a transparent, low-colored film can be obtained at a glass transition temperature of 300 ° C. or higher from a polyimide resin solution prepared from 1,2,4,5-cyclohexanetetracarboxylic dianhydride and diaminodiphenyl ether. (See Patent Document 6). Since the method of patent document 5 contains a high temperature imidation process similarly to the conventional method, coloring prevention property is inadequate, and the polyimide resin films described in both patent documents have high water absorption and high moisture absorption dimensional stability Had falling flaws

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-158816

Patent Document 2: Japanese Patent Application Laid-Open No. 4-248864

Patent Document 3: Japanese Patent Application Laid-Open No. 8-143666

Patent Document 4: Japanese Patent Application Laid-Open No. 8-225645

Patent Document 5: US Patent No. 3,639,343

Patent Document 6: Japanese Patent Application Laid-Open No. 2003-168800

Disclosure of the Invention

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to be excellent in flexibility, heat resistance, transparency, and dimensional stability, and is suitable for optical applications such as substrate materials, such as flat panel displays and mobile phone devices, optical fibers, optical waveguides, and optical adhesives. It is to provide an absorbent polyimide resin.

Another object of the present invention is colorless, transparent, and high heat resistance suitable as a sealing material for photoelectric conversion devices such as LEDs and optical sensors, which enables mounting using lead-free solder and also obtains high light extraction efficiency. Moreover, it is providing the low water absorption polyimide resin which has high refractive index and little coloring at high temperature.

Another object of the present invention is to provide a method for producing a film made of the polyimide resin.

Moreover, the objective of this invention is providing the sealing material containing the said polyimide resin.

MEANS TO SOLVE THE PROBLEM The present inventors earnestly examined in order to achieve the said objective, and, as a result, from the compound chosen from specific alicyclic tetracarboxylic acid, alicyclic tetracarboxylic dianhydride, and these reactive derivatives, and diamine and diisocyanate which have a specific structure, It discovered that the polyimide resin obtained by the imidation reaction with the compound selected has low water absorption, maintaining high heat resistance and transparency, and came to this invention.

That is, the present invention is the following formula 1:

1,2,4,5-cyclohexanetetracarboxylic acid represented by the following formula 2:

At least one acyl-containing compound selected from the group consisting of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and these reactive derivatives;

At least one represented by (wherein X is -NH ₂ or -N = C = O, n is an integer of 0 to 4, p is 0 or 1, and n + p is an integer of 1 to 5) Provided are a method for producing a polyimide resin comprising a step of reacting at least one imino-forming compound selected from compounds having a phenylene group and an isopropylidene group.

Moreover, this invention obtained by the said manufacturing method, following formula 4:

Provided is a polyimide resin comprising a repeating unit represented by (wherein n and p are the same as above).

Moreover, this invention provides the method of manufacturing a polyimide film from the solution containing the polyimide resin obtained by the said manufacturing method, and the sealing material for photoelectric conversion devices containing the said polyimide resin.

To practice the invention  Preferred form for

The polyimide resin of the present invention is represented by the following formula 1:

1,2,4,5-cyclohexanetetracarboxylic acid represented by the following formula 2:

At least one acyl-containing compound selected from the group consisting of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and these reactive derivatives;

At least one represented by (wherein X is -NH ₂ or -N = C = O, n is an integer of 0 to 4, p is 0 or 1, and n + p is an integer of 1 to 5) It is produced by reacting at least one imino-forming compound selected from compounds having a phenylene group and an isopropylidene group in an organic polar solvent.

As said acyl containing compound, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic acid, 1,2,4,5-cyclohexane tetracarboxylic acid monomethyl ester , 1,2,4,5-cyclohexanetetracarboxylic acid dimethyl ester, 1,2,4,5-cyclohexanetetracarboxylic acid trimethyl ester, 1,2,4,5-cyclohexanetetracarboxylic acid tetramethyl ester, 1,2 , 4,5-cyclohexanetetracarboxylic acid monoethyl ester, 1,2,4,5-cyclohexanetetracarboxylic acid diethyl ester, 1,2,4,5-cyclohexanetetracarboxylic acid triethyl ester, 1,2,4 And 5-cyclohexanetetracarboxylic acid tetraethyl ester, and the like, and 1,2,4,5-cyclohexanetetracarboxylic dianhydride is preferable. These can be used individually or in mixture of 2 or more types.

Examples of the imino-forming compound include 2,2-bis (3-aminophenyl) propane, 2,2-bis (4-aminophenyl) propane, 1,3-bis (3-amino-α, α-dimethylbenzyl ) Benzene, 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene, 1,4-bis (3-amino-α, α-dimethylbenzyl) benzene, 1,4-bis (4-amino -α, α-dimethylbenzyl) benzene, 2,2-bis [4- (3-amino-α, α-dimethylbenzyl) phenyl] propane, 2,2-bis [4- (4-amino-α, α -Dimethylbenzyl) phenyl] propane, 2,2-bis (3-isocyanatophenyl) propane, 2,2-bis (4-isocyanatophenyl) propane, 1,3-bis (3-isocy Anato-α, α-dimethylbenzyl) benzene, 1,3-bis (4-isocyanato-α, α-dimethylbenzyl) benzene, 1,4-bis (3-isocyanato-α, α -Dimethylbenzyl) benzene, 1,4-bis (4-isocyanato-α, α-dimethylbenzyl) benzene, 2,2-bis [4- (3-isocyanato-α, α-dimethylbenzyl ) Phenyl] propane, 2,2-bis [4- (4-isocyanato-α, α-dimethylbenzyl) phenyl] propane, m-α, α, α ', α' -Tetramethylxylylenediamine, m-α, α, α ', α'-tetramethylxylylene diisocyanate, 2,2-bis- [4- (dimethylaminomethyl) phenyl] propane and 2,2- Bis- [4- (dimethylisocyanatomethyl) phenyl] propane, and the like, and a diamine compound (a compound in which two X in Formula 3 is -NH ₂ ) is preferable. These can be used individually or in mixture of 2 or more types.

In addition to the above imino-forming compound, other diamines may be used as necessary in order to control various physical properties such as heat resistance, thermal expansion coefficient, dielectric constant, refractive index, or birefringence in a range that does not impair the good low water absorption of the polyimide resin. You may use together 1-49 mol% of a furnace formation compound.

Although the diamine which can be used together is not limited, For example, m-phenylenediamine, p-phenylenediamine, 4,4'- diamino diphenyl ether, 3,3'- diamino diphenyl ether, 4 , 4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diamino Benzophenone, 3,3'-diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-amino Phenoxy) benzene, 4,4'-bis (3-aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] Sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, bis [4 -(3-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] propane, bis (4-aminocyclohexyl) methane, m-xylylenediamine, p-xylylenediamine Isophorone There may be mentioned amines or the like.

Although the organic polar solvent used for the manufacturing method of this invention is not specifically limited, It is preferable that it is an aprotic organic polar solvent. For example, γ-butyrolactone, N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, p-chlorophenol, m-cresol and tetra Hydrofuran etc. are mentioned. Among them, colorlessness and transparency are improved by using γ-butyrolactone and N, N-dimethylacetamide. These solvent can be used individually or in mixture of 2 or more types.

The manufacturing method of the polyimide film using the manufacturing method of the polyimide resin of this invention, and the organic polar solvent solution of the obtained polyimide resin is demonstrated below.

Preparation of Polyimide Resin Solution

At least one imino-forming compound is dissolved in an organic polar solvent. It is preferable to dissolve 10-30 weight part of imino-forming compounds with respect to 100 weight part of organic polar solvents. After adding at least 1 type of acyl containing compound in -5 degreeC-room temperature vicinity to the obtained solution, it hold | maintains for 30 to 60 minutes at the temperature of room temperature vicinity-100 degreeC, and manufactures a polyamic-acid solution.

The total amount of the at least one imino-forming compound and the at least one acyl-containing compound in the reaction solution is preferably 20 to 50% by weight, more preferably 30 to 40% by weight of the total amount of the reaction solution. If it is 20 weight% or more, the polyimide resin of appropriate intrinsic viscosity can be obtained. If it is 50 weight% or less, the intrinsic viscosity of a polyimide resin can be prevented from increasing excessively, the viscosity of a polyimide resin solution becomes too high and uniform stirring becomes difficult, and the problem of resin sticking can be avoided.

Subsequently, an imidization catalyst is added as needed, and dehydration reaction is performed, while heating and refluxing out of system water until outflow of product water is carried out, and a polyimide resin solution is obtained. The imidation catalyst may be tertiary amines such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, pyridine, and β-picolin; Inorganic acids such as phosphorous acid, phosphoric acid, hydrochloric acid and perchloric acid; Organic acids such as crotonic acid and benzoic acid. Among them, preference is given to using tertiary amines in particular. As for the addition amount of an imidation catalyst, 1-10 mol% of an acyl containing compound is preferable.

Instead of the above method, acyl-containing compounds, imino-forming compounds, organic polar solvents, and if necessary, the imidization catalyst is put in a batch, and then heating is started, and dehydration imidization is also preferably carried out immediately.

The molar ratio between the imino-forming compound and the acyl-containing compound is preferably 0.95 to 1.05, more preferably 0.99 to 1.01. If it is in the said range, the colorless transparent polyimide resin of suitable logarithmic viscosity (0.5-2.0) can be obtained, and the polyimide film of sufficient strength can be obtained.

The reaction temperature of dehydration imidation becomes like this. Preferably it is 160-200 degreeC, More preferably, it is 170-190 degreeC, More preferably, it is 180-190 degreeC. If it is in the said range, high molecular weight will fully advance and a solution viscosity will increase remarkably and defects, such as resin sticking to the wall surface of a reaction container, can be avoided. In some cases, azeotropic dehydrating agents such as toluene and xylene may be used. Although dehydration imidation time depends on the reactivity of an imino-forming compound, 3 to 12 hours are preferable and 6 to 8 hours are more preferable.

Usually, a polyimide resin solution is prepared by the above method, but a polyamic acid solution is prepared as a third production method, and a dehydrating agent such as acetic anhydride and a known tertiary amine are added thereto at 100 to 120 ° C. It imidated for 3 to 6 hours, added the poor solvent with respect to polyimide, such as methanol, and precipitated a polyimide resin, isolate | separates a polyimide resin as a solid by filtration, washing, and drying, and organically It is also possible to obtain a polyimide resin solution by dissolving in a polar solvent.

As an organic polar solvent which melt | dissolves a polyimide resin, (gamma) -butyrolactone, N, N- dimethylacetamide, N, N- dimethylformamide, N-methyl- 2-pyrrolidone, dimethyl sulfoxide, hexamethyl Phosphoamide, p-chlorophenol, m-cresol, tetramethylene sulfone, propylene carbonate and the like. You may use these solvent in mixture of 2 or more types. Moreover, cyclic ethers, such as tetrahydrofuran, 1, 4- dioxane, and 1, 3- dioxolane, and cyclic | annulars, such as cyclohexanone and cyclopentanone, in the range in which the solubility of resin does not become low. Ketones can also be used together.

The polyimide resin obtained by each said manufacturing method has following formula 4:

In the formula, n and p are the same as above. The repeating unit is preferably 51 mol% or more (including 100%). Other repeating units are derived from the diamines optionally used above. Moreover, it is preferable that it is 10-50 weight%, and, as for the polyimide resin concentration in the polyimide resin solution obtained by each said manufacturing method, it is more preferable that it is 20-30 weight%.

Preparation of Polyimide Film

When the polyimide resin solution prepared by the above method is cast into a glass substrate or a stainless steel substrate to which mold release property is imparted, and is formed into a film shape, and the film has self-supportability on a hot plate or in a drying furnace. Pre-dry for about 30-60 minutes at a temperature of 80-120 ℃. Subsequently, after removing the film from the substrate and fixing both ends, the film is kept at least at the boiling point of the solvent used, preferably at a temperature higher than the boiling point, preferably 5 to 10 ° C., for one hour so as not to cause the residual solvent to dwell while limiting the shrinkage of the film. The temperature is raised over and vacuum dried at this temperature to obtain a polyimide resin film.

The time to perform the vacuum drying also depends on the film thickness of the film. For example, in the case of the film for the plastic substrate for flexible display of 150 to 200 μm, 5 to 48 hours is preferable to make the residual solvent less than 1% More preferably, it is 8 to 24 hours.

In order to cast a polyimide resin solution to a glass substrate or the board | substrate made from stainless steel, you may use any film | membrane manufacturing method, such as a well-known dry and wet-type shaping | molding method. For example, the casting method by die extrusion, the method of using an applicator, a coater, etc. are mentioned. Moreover, it can also cast on the film of organic polymers, such as polyethylene terephthalate and polyethylene naphthalate.

In order to improve the characteristics, such as surface smoothness and mold release property of a polyimide resin film, various surfactant, internal mold release agent, etc. can be added at arbitrary stages of manufacture.

After apply | coating the polyimide resin solution obtained by the said method on a photoelectric conversion element, it is excellent in heat resistance by volatilizing an organic solvent, the resin sealing part which has high refractive index can be formed, and the outstanding photoelectric conversion device can be obtained. Moreover, fluorescent material etc. may be mixed with LED sealing resin for the purpose of converting a light emission wavelength into a visible region. Since the polyimide resin of this invention is excellent in mixing property, dispersibility, and stability when it mixes with various fluorescent materials, it is preferable as a sealing material for LED. Moreover, it is also possible to form the lens of arbitrary transparent resins on the surface of a resin sealing part for the purpose of control of a light emission direction. Since the light introduced into the resin lens is converted into visible light of low energy in the resin encapsulation portion, it exhibits sufficient durability even in lenses such as general-purpose epoxy resins. Since the polyimide resin of this invention has favorable adhesiveness with lenses, such as an epoxy resin, it is especially preferable as a sealing material of LED.

Hereinafter, an Example demonstrates this invention concretely. However, the present invention is not limited to these Examples at all.

In addition, the physical property of the polyimide resin and polyimide film obtained by the Example and the comparative example was measured by the method shown below.

(1) logarithmic viscosity

A part of the polyimide resin solution was poured into anhydrous methanol to precipitate the polyimide resin, and filtered to separate from the unreacted monomer. 0.1 g of polyimide obtained by vacuum drying at 80 ° C. for 12 hours was dissolved in 20 mL of N-methyl-2-pyrrolidone, and the logarithmic viscosity (μ) at 30 ° C. was obtained by using a Canon-Penske viscometer. Obtained by

μ = {1n (t _s / t _o )} / C

t _o : dropping time of solvent

t _s : dripping time of lean polymer solution

C: 0.5 g / dL

(2) glass transition temperature (Tg)

Using a DSC-40M differential thermal analysis device manufactured by Shimadzu Corporation, the temperature of the polyimide film was raised to 400 ° C at 10 ° C / min in a nitrogen atmosphere, and the glass transition temperature was measured.

(3) absorption rate measurement

The polyimide film having a thickness of about 25 μm was dried at 150 ° C. for 1 hour. The weight after holding in a desiccator for 1 hour was made into W1, it was immersed in 23 degreeC distilled water for 24 hours, and the weight after wiping off the water droplet on the surface was computed by the following formula.

Absorption (%) = (W2-W1) ÷ W1 × 100

(4) total light transmittance and YI value

The total light transmittance and the YI value of the polyimide film were measured using a color difference / turbidity meter COI-300A manufactured by Nippon Color Industry Co., Ltd. as an index for evaluating colorlessness and transparency according to the JIS K7105 transparency test method.

(5) refractive index

589 nm interference filter was set using the refractive index measuring apparatus (DR-M2) by the Atago Co., Ltd., and the refractive index was measured at 23 degreeC.

(6) heat resistance acceleration test

A 50 × 50 mm test film was placed in a hot air drier maintained at 150 ° C., and the change in light transmittance and YI value at 400 nm was tracked.

Reference Example  1 <1,2,4,5- Cyclohexanetetracarboxylic acid Dianhydride  Synthesis>

Into a 5 liter Hastelloy (HC22) autoclave, 200 g of a catalyst (manufactured by NEChemcat Corporation) with 552 g of pyromellitic acid and Rh supported on activated carbon, and 1656 g of water were added thereto. While stirring, the inside of the autoclave was replaced with hydrogen gas, and the temperature was raised to 60 ° C with a hydrogen pressure of 5.0 MPa. The reaction was carried out for 2 hours while maintaining the hydrogen pressure at 5.0 MPa. Hydrogen gas in the autoclave was replaced with nitrogen gas and the reaction liquid was withdrawn from the autoclave. The reaction solution was filtered while hot to separate the catalyst. Crystals were precipitated by distilling off water from the filtrate under reduced pressure using a rotary evaporator. The precipitated crystals were solid-liquid separated at room temperature and dried to obtain 481 g (yield 85.0%) of 1,2,4,5-cyclohexanetetracarboxylic acid.

Subsequently, 481 g of the obtained 1,2,4,5-cyclohexanetetracarboxylic acid and 400 g of anhydrous acetic acid were put into a 5 liter glass separable flask, and the inside of the flask was replaced with nitrogen gas, stirring. The temperature was raised to the reflux temperature of the solvent under nitrogen gas atmosphere and the solvent was refluxed for 10 minutes. It cooled to room temperature with stirring, and the crystal | crystallization precipitated. The precipitated crystals were solid-liquid separated and dried to obtain primary crystals. In addition, the separated mother liquor was concentrated under reduced pressure with a rotary evaporator to precipitate crystals. This crystal was solid-liquid separated and dried to obtain a secondary crystal. 375 g of 1,2,4,5-cyclohexanetetracarboxylic dianhydride was obtained by combining primary crystals and secondary crystals (yield yield 96.6%).

Example 1

1,3-bis (4-amino-α, α-dimethylbenzyl) benzene (BisA-M, Alias) in a 500 mL five-necked flask equipped with a thermometer, agitator, nitrogen introduction tube and cooling tube with fractionator 34.58 g (0.1 mol) of: 4,4 '-(m-phenylenediisopropylidene) dianiline) were dissolved in a solvent (68.65 g of γ-butyrolactone and 17.16 g of N, N-dimethylacetamide). The resulting solution was cooled to 5 ° C. using an ice water bath. While maintaining the same temperature, 22.62 g (0.1 mol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and 0.50 g (0.005 mol) of triethylamine as an imidization catalyst were added all at once. After the addition was completed, the temperature was raised to 180 ° C., and the effluent was refluxed for 8 hours with distillation from time to time. After the completion of the reaction, the mixture was cooled by air until the internal temperature reached 100 ° C, and 143.6 g of N, N-dimethylacetamide was added thereto, diluted, and cooled with stirring to obtain a polyimide resin solution having a solid content concentration of 20% by weight. The weight of this polyimide resin solution was 262.47 g, and the total weight of the effluent was 4.86 g. A part of the polyimide resin solution was poured into 1 L of methanol to precipitate the polyimide. The polyimide separated by filtration was washed with methanol, and then dried in a vacuum dryer at 100 ° C. for 24 hours to obtain a white powder. When the IR spectrum of this powder was measured, absorption of 1702 cm ^-1 and 1772 cm ^-l peculiar to the imide group was observed. It was 0.94 when the logarithmic viscosity of the polyimide was measured.

The above-mentioned polyimide resin solution was prepared using a 1000 μm doctor blade to release a plastic release agent (Chukyo Kasei Kogyo Co., Ltd.) “Pericote”. Cast on a uniformly applied stainless steel substrate. This was hold | maintained at 100 degreeC for 60 minutes on a hotplate, the solvent was volatilized and the colorless transparent primary dry film which has self-supportability was obtained. The film was fixed to a stainless steel mold, vacuum dried at 200 ° C. for 8 hours to remove residual solvent, thereby obtaining a colorless and transparent polyimide film having a film thickness of 117 μm. The total light transmittance, YI value, water absorption and glass transition temperature of this film were measured. The results are shown in Table 1.

Example  2

1,4-bis (4-amino-α, α-dimethylbenzyl) benzene Instead of 34.58 g (0.1 mol) 1,4-bis (4-amino-α, α-dimethylbenzyl) benzene (BisA-P) 27.66 242.33 g of a polyimide resin solution was obtained in the same manner as in Example 1 except that g (0.08 mol) and 2.16 g (0.02 mol) of m-phenylenediamine (MPD) were changed to 6 hours. . A white powder was obtained in the same manner as in Example 1, and the IR spectrum of this powder was measured. As a result, absorption of 1704 cm ^-l and 1770 cm ^-l specific to the imide group was observed. It was 1.01 when the logarithmic viscosity of the polyimide was measured.

Using the polyimide resin solution prepared above, it carried out similarly to Example 1, and obtained the polyimide film with a film thickness of 122 micrometers. The total light transmittance, YI value, water absorption and glass transition temperature of this film were measured. The results are shown in Table 1.

Example  3

1,4-bis (4-amino-α, α-dimethylbenzyl) benzene Instead of 34.58 g (0.1 mol) 1,4-bis (4-amino-α, α-dimethylbenzyl) benzene (BisA-P) 27.66 Same as Example 1 except using g (0.08 mol) and 7.38 g (0.02 mol) of 4,4'-bis (4-aminophenoxy) biphenyl (BAPB), and changing the reflux time to 6 hours. 264.16 g of a polyimide resin solution was obtained. In the same manner as in Example 1, a white powder was obtained, and the IR spectrum of this powder was measured. As a result, absorption of 1704 cm ^-l and 1770 cm ^-l peculiar to the imide group was observed. The logarithmic viscosity of the polyimide was measured and found to be 0.87.

Using the polyimide resin solution prepared above, in the same manner as in Example 1, a colorless and transparent polyimide film having a film thickness of 112 μm was obtained. The total light transmittance, YI value, water absorption and glass transition temperature of this film were measured. The results are shown in Table 1.

Example  4

M-α, α, α ', α'-tetramethylxylylenediisocyanate (m-TMDI) instead of 34.58 g (0.1 mol) of 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene 24.52 214.16 g of a polyimide resin solution was obtained in the same manner as in Example 1 except that g (0.1 mol) was used. A white powder was obtained in the same manner as in Example 1, and the IR spectrum of this powder was measured. As a result, absorption of 1698 cm ^-l and 1776 cm ^-l peculiar to the imide group was observed. It was 0.72 when the logarithmic viscosity of the polyimide was measured.

Using the polyimide resin solution prepared above, it was carried out similarly to Example 1, and obtained the colorless and transparent polyimide film of 112 micrometers in film thickness. The total light transmittance, YI value, water absorption and glass transition temperature of this film were measured. The results are shown in Table 1.

Comparative example  One

19.83 g (0.1 mol) of bis (4-aminophenyl) methane (DDM) was used instead of 34.58 g (0.1 mol) of 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene and the reflux time was 210.50 g of a polyimide resin solution was obtained in the same manner as in Example 1 except that the result was changed to 6 hours. The same manner as Example 1 to obtain a white powder, a result of measuring an IR spectrum of the powder, there was shown a characteristic absorption of 1700cm ^-1, 1768 cm ^-1 of deugi. It was 1.04 when the logarithmic viscosity of the polyimide was measured.

Using the polyimide resin solution prepared above, it was carried out similarly to Example 1, and obtained the colorless and transparent polyimide film of 108 micrometers in thickness. The total light transmittance, YI value, and glass transition temperature of this film were measured. The results are shown in Table 1.

Comparative example  2

10.11 g (0.05 mol) of bis (4-aminophenyl) methane and m-phenylenediamine (MPD) instead of 34.58 g (0.1 mol) of 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene 210.50 g of a polyimide resin solution was obtained in the same manner as in Example 1 except that g (0.05 mol) was used and the reflux time was changed to 6 hours. A white powder was obtained in the same manner as in Example 1, and the IR spectrum of this powder was measured. As a result, absorption of 1701 cm ^-1 and 1769 cm ^-1 specific to the imide group was observed. The logarithmic viscosity of the polyimide was measured and found to be 0.67.

Using the polyimide resin solution prepared above, it was carried out similarly to Example 1, and obtained the colorless and transparent polyimide film of 106 micrometers in thickness. The total light transmittance, YI value, and glass transition temperature of this film were measured. The results are shown in Table 1.

Comparative example  3

20.10 g (0.1 mol) of bis (4-aminophenyl) ether (oxydianiline, ODA) instead of 34.58 g (0.1 mol) of 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene 205.05 g of polyimide resin solution was obtained in the same manner as in Example 1 except that the reflux time was changed to 3 hours. A white powder was obtained in the same manner as in Example 1, and the IR spectrum of this powder was measured. As a result, absorption of 1691 cm ^-1 and 1764 cm ^-1 specific to the imide group was observed. The logarithmic viscosity of the polyimide was measured and found to be 1.21.

Using the polyimide resin solution prepared above, it was carried out similarly to Example 1, and obtained the colorless and transparent polyimide film of 115 micrometers in thickness. The total light transmittance, YI value, and glass transition temperature of this film were measured. The results are shown in Table 1.

Comparative example  4

43.25 g (0.1 mol) of bis [4- (4-aminophenoxy) phenyl] sulfone (BAPS) was substituted for 34.58 g (0.1 mol) of 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene Except having changed the reflux time into 6 hours using, it carried out similarly to Example 1, and obtained 311.92g of polyimide resin solutions. A white powder was obtained in the same manner as in Example 1, and the IR spectrum of this powder was measured. As a result, absorption of 1704 cm ^-l and 1772 cm ^-l peculiar to the imide group was observed. It was 0.90 when the logarithmic viscosity of the polyimide was measured.

Using the polyimide resin solution prepared above, it was carried out similarly to Example 1, and obtained the colorless and transparent polyimide film with a film thickness of 116 micrometers. The total light transmittance, YI value, and glass transition temperature of this film were measured. The results are shown in Table 1.

Example  5

The polyimide resin powder obtained by carrying out similarly to Example 2 was melt | dissolved in 1, 3- dioxolane (boiling point 78 degreeC), and the polyimide resin solution of 20 weight% of solid content concentration was adjusted. This solution was cast onto a glass substrate uniformly coated with a release agent for plastics using a doctor blade of 2000 μm. Next, the substrate was kept at 60 ° C for 1 hour and 90 ° C for 1 hour on a hot plate to volatilize the solvent, and then dried at 150 ° C in a hot air dryer for 3 hours. The film formed on the board | substrate after cooling was peeled off, and the colorless and transparent dry polyimide film was obtained. Table 2 shows the results of the film thickness, refractive index, and heat resistance acceleration test of this film.

Comparative example  5

38 g of bisphenol A type liquid epoxy resins (Japan Epoxy Resin Co., Ltd., Epicoat 828US, epoxy equivalent 190), 32.8 g of methylhexahydrophthalic anhydride (New Nippon Chemical Co., Ltd., lycaside MH-700G, 1.0 equivalent), and 0.35 g of 2-ethyl-4-methylimidazole as a curing accelerator was weighed into a 100 ml beaker and mixed well with a stirring rod to prepare an epoxy resin mixture. 3 g of an epoxy resin mixture was introduced into a silicone resin mold having a dimension of 60 × 60 × 10 mm. The resin mold was placed on a glass substrate, placed horizontally in a hot air dryer, and cured at 90 ° C. for 1 hour, 120 ° C. for 3 hours, and 150 ° C. for 3 hours. After cooling, a colorless and transparent sheet-like cured product was obtained from the resin mold. Table 2 shows the results of the thickness, refractive index, and heat resistance acceleration test of this sheet-like cured product.

As can be seen from the comparison between Examples 1 to 4 and Comparative Examples 1 to 4, since the polyimide resin according to the present invention has high heat resistance, high transparency and low water absorption, substrate materials such as flat panel displays and mobile telephone devices, It is suitable for optical applications such as optical fibers, optical waveguides, and optical adhesives. In addition, as can be seen from the comparison between Example 5 and Comparative Example 5, the polyimide film of the present invention has a small refractive index and a high refractive index at the time of high temperature exposure, and thus have a high refractive index. It is suitable as a sealing material of photoelectric conversion devices, such as (LED) and an optical sensor.

Claims (8)

Equation 1:

1,2,4,5-cyclohexanetetracarboxylic acid represented by the following formula 2:

At least one acyl-containing compound selected from the group consisting of 1,2,4,5-cyclohexanetetracarboxylic dianhydride and these reactive derivatives;

At least one of which is represented by (wherein X is -NH ₂ or -N = C = 0, n is an integer of 0 to 4, p is 0 or 1, and n + p is an integer of 1 to 5) A method for producing a polyimide resin comprising a step of reacting at least one imino-forming compound selected from compounds having a phenylene group and an isopropylidene group. The method of claim 1, A method for producing a polyimide resin, wherein the reaction is carried out in an organic polar solvent solution in the presence of an imidization catalyst under heating to obtain a polyimide resin solution. The method of claim 2, The said imidation catalyst is a manufacturing method of the polyimide resin which is a tertiary amine. The method of claim 2 or 3, The manufacturing method of the polyimide resin which performs the said heating at 160-200 degreeC for 3 to 12 hours. Equation 4:

The polyimide resin containing the repeating unit represented by (in formula, n and p are the same as the above.). The manufacturing method of the polyimide film containing the process of casting the polyimide resin solution of Claim 2 or the organic polar solvent solution of the polyimide resin of Claim 5 on a board | substrate, and evaporating and removing a solvent from the obtained cast film. The method of claim 6, After evaporating and removing the solvent from the cast film at 80-120 ° C. to obtain a self-supporting film, the self-supporting film was vacuum dried at a temperature of the boiling point of the solvent to the boiling point of the solvent + 10 ° C. to further remove the solvent. Method for producing a polyimide film. The sealing material for photoelectric conversion devices containing the polyimide resin of Claim 5.